1. Field of the Invention
The present invention relates to processing systems and more particularly, but not necessarily exclusively to welding systems to manufacture tailored blanks.
2. Description of the Related Art
The automobile industry has, over the years, achieved significant improvements in the operating efficiency of the automobiles they produce. This has, in large part, been achieved by the reduction in the weight of the vehicle while maintaining its structural integrity. A major proportion of the weight of the vehicle is from its steel components, such as the chassis and doors, hood and trunk lids. Often, there are areas in the structure of these components that need to remain of a greater thickness, such as in the region of the door hinges, while there are other areas, such as in the door frame, that can be of relatively thinner wall. It is common in this case to reinforce the otherwise relatively thin door frame in the regions to carry the hinges with a stiffener to provide the necessary reinforcement. However, this step increases the parts count and is a source for additional cost.
The automobile industry has, in recent years, been working to implement a welding process to fabricate what is popularly known as a tailored blank which has a relatively thick portion which is welded to a relatively thin portion, so that it can be later stamped into a part with a thick portion being in place to provide strength, reduce the overall part count and weight.
A significant improvement to laser welding lines is disclosed in U.S. Pat. No. 6,204,469 entitled LASER WELDING SYSTEM, assigned to HONDA GIKEN KOGYO KABUSHIKI KAISHA. The subject matter of this patent is incorporated herein by reference. This will be referred to as the Honda ""469 patent.
While the system described in the ""469 patent has provided a substantial increase in the speed, accuracy and integrity of tailored blanking welds, there is a continuing need to make further improvements, particularly in the speed of the operation.
Accordingly, the present invention seeks to improve certain aspects of the welding processes such as those used to form tailored blanks.
In one of its aspects a laser welding system, comprising:
a travel path to carry a first blank and a second blank, the first blank having a first weld surface and the second blank having a second weld surface, the first and second blanks being ready to be welded together to form a weld seam along the first and second weld surfaces;
an upstream clamp assembly and a downstream clamp assembly positioned on the travel path;
each of the upstream and downstream clamp assemblies being movable to an open position to allow the first blank to pass through the upstream clamp assembly to a first location within the downstream clamp assembly;
a laser welding source directed at a weld location on the travel path between the upstream and downstream clamp assemblies;
at least one locating means operable to locate the first weld edge adjacent the weld location;
first displacement means to displace the first weld edge against the locating means;
the downstream clamp assembly being movable from the open position to a closed clamped position to clamp the first blank with the first weld edge adjacent the weld location;
the locating means being operable to be withdrawn from the travel path;
the upstream clamp assembly being movable from the open position to an intermediate position, which is selected to guide the second blank to pass through the upstream clamp assembly in a substantially coplanar relationship with the first blank so that the second weld edge makes contact with, but not past, the first weld edge;
second displacement means to displace the second blank to a location adjacent the weld location where the second weld edge abuts the first weld edge;
the upstream clamp assembly being movable from the intermediate position to a closed clamped position to clamp the second blank;
the laser welding unit operable to fuse the first and second weld edges blanks together.
In one embodiment, the system further comprises first and second lateral positioning means for respectively positioning the first and second blanks relative to the travel path. Each blank has a pair of side edges and each lateral positioning means includes a pair of lateral abutment members, each for engaging a corresponding side edge, and a lateral servo positioner for positioning each lateral abutment member. Lateral control means is provided for incrementally controlling the lateral servo positioners. Each of the lateral abutment members includes an upwardly directed flange and a plurality of stop members mounted on the flange.
In one embodiment, each of the claim assemblies includes an upper clamp beam and a lower clamp beam, a plurality of clamp elements fastened to the upper beam and a clamp drive unit for displacing the upper clamp beam relative to the lower clamp between the open and closed positions.
In one embodiment, the first displacement means includes at least one first engagement portion for engaging the first blank and a first drive portion for driving the first engagement portion. The first engagement portion includes a first engagement member, in the form of an upwardly directed flange and a blank abutment member mounted on the flange, for engaging an edge on the first blank opposite the first weld edge and the first drive portion includes a first servo positioner which is aligned for movement along the travel path for displacing the first engagement member; and first control means for incrementally controlling the first servo positioner. A first actuator unit is provided for actuating the blank abutment member between an operable position in the travel path and an inoperable position below the travel path.
In one embodiment, the second displacement means includes at least one second engagement portion for engaging the second blank and a second drive portion for driving the second engagement portion. The second engagement portion includes a second engagement member, in the form of an upwardly directed flange and a blank abutment member mounted on the flange, for engaging an edge of the second blank opposite the second weld edge and the second drive portion includes a second servo positioner which is aligned for movement along the travel path for displacing the second engagement member; and second control means for incrementally controlling the second servo positioner. A second actuator unit is provided for actuating the blank abutment member between an operable position in the travel path and an inoperable position below the travel path.
In one embodiment, the locating means includes a locating member movable between an operable position in the travel path and an inoperable position below the travel path and a locating drive assembly for driving the locating member between the operative and inoperative positions. The locating drive assembly has a carriage member mounted for lateral movement relative to the travel path on a third servo positioner, the carriage supporting a vertically oriented actuator with an output shaft coupled to the locating member. A third control means is also provided for incrementally controlling the third servo positioner.
In still another of its aspects, the present invention provides a method of welding a pair of blanks, comprising:
a step for providing a travel path to carry a first blank and a second blank;
a step for providing an upstream clamp assembly and a downstream clamp assembly positioned on the travel path;
a step for opening the upstream and downstream clamp assemblies;
a step for conveying a first blank along the travel path and through the upstream clamp assembly to the downstream clamp assembly;
a step for positioning a laser welding unit at a weld location between the upstream and downstream clamp assemblies;
a step for interrupting the travel path at the weld location with at least one blank locator;
a step for displacing the first blank until its trailing to-be-welded edge abuts the locator;
a step for clamping the downstream clamp assembly to clamp the first blank in its position against the locator;
a step for withdrawing the locator from the travel path;
a step for moving the upstream clamp assembly to an intermediate position;
a step for conveying a second blank along the travel path to the upstream clamp assembly;
a step for displacing the second blank until its leading to-be-welded edge makes edge-to-edge contact with, but does not pass over, the trailing to-be-welded edge of the first blank;
a step for closing the upstream clamp assembly; and
a step for operating the laser welding unit to form a weld seam along the abutting edges of the first and second blanks.
In still another of its aspects, the present invention provides a laser welding system, comprising:
a travel path to carry a first blank and a second blank;
an upstream clamp assembly and a downstream clamp assembly positioned on the travel path;
each of the upstream and downstream clamp assemblies being movable to an open position to allow the first blank, in a first step, to pass through the upstream clamp assembly and be delivered to the downstream clamp assembly;
a laser welding unit positioned at a weld location between the upstream and downstream clamp assemblies; at least one locating means operable, in a second step, to interrupt the travel path at the weld location;
first displacement means operable, in a third step, to displace the first blank until its trailing to-be-welded edge abuts the locating means;
the downstream clamp assembly movable, in a fourth step, from the open position to a closed clamped position to clamp the first blank;
the locating means operable, in a fifth step, to be withdrawn from the travel path;
the upstream clamp assembly movable, in a sixth step, from the open position to an intermediate position, to allow a second blank to be delivered to the upstream clamp assembly;
second displacement means, operable in a seventh step with the upstream clamp assembly to displace the second blank until its leading to-be-welded edge makes edge-to-edge contact therewith, while guiding constraining movement of the second blank to prevent the second blank from passing over the trailing to-be-welded edge of the first blank;
the upstream clamp assembly movable, in an eighth step, from the intermediate position to a closed clamped position to clamp the second blank;
the laser welding unit operable, in a ninth step, to fuse the first and second blanks together along their abutting edges.
In still another of its aspects, the present invention provides a clamping system, comprising:
a travel path to carry a first blank and a second blank;
an upstream clamp assembly and a downstream clamp assembly positioned on the travel path;
each of the upstream and downstream clamp assemblies movable to an open position to allow the first blank, in a first step, to pass through the upstream clamp assembly and be delivered to the downstream clamp assembly;
at least one locating means operable, in a second step, to interrupt the travel path between the upstream and downstream clamp assemblies;
first displacement means operable, in a third step, to displace the first blank until one edge abuts the locating means;
the downstream clamp assembly movable, in a fourth step, from the open position to a closed clamped position to clamp the first blank;
the locating means operable, in a fifth step, to be withdrawn from the travel path;
the upstream clamp assembly movable, in a sixth step, from the open position to an intermediate position, to allow a second blank to be delivered to the upstream clamp assembly;
second displacement means operable, in a seventh step with the upstream clamp assembly to displace the second blank until one edge makes edge-to-edge contact therewith, while constraining movement of the second blank to prevent the second blank from passing over the edge of the first blank; and
the upstream clamp assembly movable, in an eighth step, from the intermediate position to a closed clamped position to clamp the second blank.
In still another of its aspects, the present invention provides a method of processing a pair of blanks along a pair of abutting edges, comprising:
a step for providing a travel path to carry a first blank and a second blank;
a step for providing an upstream clamp assembly and a downstream clamp assembly positioned on the travel path;
a step for opening the upstream and downstream clamp assemblies;
a step for conveying a first blank along the travel path and through the upstream clamp assembly to the downstream clamp assembly;
a step for positioning a processing unit between the upstream and downstream clamp assemblies;
a step for interrupting the travel path adjacent the processing unit with at least one blank locator;
a step for displacing the first blank until its trailing to-be-processed edge abuts the locator;
a step for clamping the downstream clamp assembly to clamp the first blank in its position against the locator;
a step for withdrawing the locator from the travel path;
a step for moving the upstream clamp assembly to an intermediate position;
a step for conveying a second blank along the travel path to the upstream clamp assembly;
a step for displacing the second blank until its leading to-be-processed edge makes edge-to-edge contact with, but does not pass over, the trailing to-be-processed edge of the first blank;
a step for closing the upstream clamp assembly; and
a step for operating the processing unit to process the abutting edges of the first and second blanks.
In still another of its aspects, there is provided a conveyor system for delivering, successively, two groups of blanks of different dimensions along a travel path to a downstream processing station and for orienting each blank to arrive at the station in a precisely controlled orientation, comprising:
a continuous magnetic conveyor;
first and second lateral positioning arms, each for positioning one corresponding side edge of each blank, each of the lateral positioning arms being incrementally driven by first and second servo positioners respectively;
the first and second servo positioners being movable between an inoperative position and an operative blank-engaged position, wherein the blank-engaged position is selected to locate each blank of the first group in a precisely controlled first orientation and each blank of the second group in a precisely controlled second orientation;
a longitudinal positioning assembly operable for positioning either a leading edge or a trailing edge on the blank, said longitudinal positioning assembly being incrementally driven by a third servo positioner;
servo control means for controlling the first, second and third servo positioners, said control means being operative in:
a first phase to adjust the operative and inoperative positions according to the dimensions of the blanks in the first group,
a second phase to shuttle the first and second servo positioners between their inoperative and operative positions;
a third phase to adjust the operative and inoperative positions according to the dimensions of the blanks in the second group; and
a fourth phase to shuttle the first and second servo positioners between their inoperative and operative positions.
In one embodiment, each of the lateral positioning arms includes an upwardly directed frame member and a plurality of stop members mounted on the frame member. The magnetic conveyor has a travel path and the longitudinal positioning assembly further comprises a carriage mounted for travel along the travel path. A plurality of setting pins are provided along with one or more drive units for driving the setting pins between an operative position interrupting the travel path and an inoperable position below the travel path. The setting pins are located at a position in the travel path to engage the trailing edge of the blank.
In still another of its aspects, there is provided a method for delivering, successively, two groups of blanks of different dimensions along a travel path to a downstream processing station and for orienting each blank to arrive at the station in a precisely controlled orientation, each group of blanks having two sets of common blanks, comprising:
providing a conveyor arrangement to convey the blanks along a travel path;
providing a first pair of lateral positioning arms on opposite sides of the travel path at a first location;
providing a second pair of lateral positioning arms on opposite sides of the travel path at a second location;
incrementally controlling the position of each of the arms by a servo positioner;
processing the blanks of the first group by:
presetting the parameters of the servo positioner to define an inoperative position for each arm and an operative position wherein, in the operative position, the arms engage opposing side edge of a corresponding blank to locate the corresponding blank of the first group in a precisely controlled orientation;
delivering, successively, each blank of the first set to the first location on the travel path;
delivering, successively, each blank of the second set to the second location on the travel path;
processing the blanks of the second group by;
presetting the parameters of the servo positioner to define an inoperative position, for each arm and an operative position wherein, in the operative position, the arms engage opposing side edge of a corresponding blank to locate the corresponding blank of the second group in a precisely controlled orientation;
delivering, successively, each blank of the first set to the first location on the travel path; and
delivering, successively, each blank of the second set to the second location on the travel path.
In yet another of its aspects, the present invention provides a system for delivering blanks to a processing station, comprising:
an input location for providing a plurality of blanks to be processed;
a conveyor having an upstream end near the input location and a downstream end near the processing station;
a reject location for receiving rejected blanks;
a robotic arm operable to transfer blanks from the input location to the upstream end of the conveyor;
a blank pick up assembly coupled to the robot arm and having a plurality of engaging members for engaging the blank in order to deliver the blank to a sensing location which is spaced from the pickup location, and at least one sensing means for sensing a normal condition and a reject condition at the sensing location;
the normal condition being defined by the presence of only a single blank at the pickup assembly, wherein the robot arm is operable, in the normal condition to transfer the single blank from the sensing location to the upstream end of the conveyor;
the reject condition being defined by the presence of two or more blanks at the pickup assembly, the pickup assembly further comprising at least one supplemental engagement means operable in the reject condition to engage the two or more blanks with sufficient strength to enable the robot arm to transfer the two or more blanks from the sensing location to the reject location and thereafter to to release the two or more blanks from the pickup assembly to deliver the two or more blanks to the reject location.
In one embodiment, the engagement means includes a plurality of suction devices positioned on the pickup assembly for establishing a suction connection between the blank and the pickup assembly. The blanks are ferromagnetic and the sensing means is operable to sense changes in magnetic flux. The robotic arm has a coupling end carrying the pickup assembly, the pickup assembly further comprising a frame arrangement supporting the suction devices, the sensing means being positioned in order to be immediately adjacent the blank when the robotic arm lifts the blank from the input location, in order to sense changes in flux. The supplemental engagement means, in this case, includes one or more magnets to deliver a magnetic force to the two or more blanks, but could include such things as ultrasonic sensors and the like, provided they are capable to detecting a change in a wave or signal indicating the presence of one, or alternatively more than one, blank at the pick up assembly in the sensing location.
Preferably, the supplemental engagement means includes displacement means which is operable in the reject condition to displacing the magnet from an inoperative position in which the magnet is spaced a sufficient distance from the blank so as to exert substantially no attraction thereon to an operative position sufficiently close to the blank so as to exert a magnet attraction force thereon.
In still another of its aspects, there is provided a method for delivering blanks to a processing station, comprising the steps of:
providing an input location for providing a plurality of blanks to be processed;
providing a conveyor having an upstream end near the input location near a downstream end at the processing station;
providing a reject location for receiving rejected blanks;
providing a blank pickup unit;
lifting a blank from the input location with the pickup unit;
sensing for the presence of more than one blank at the pickup unit;
if a number of blanks are sensed, delivering the pickup unit to the reject location and releasing the blanks; and
if only one blank is sensed, delivering the blank to the upstream end of the conveyor.
In still another of its aspects, there is provided a method for delivering blanks to a processing station, comprising:
a step for providing an input location for providing a plurality of blanks to be processed;
a step for providing a conveyor having an upstream end near the input location and a downstream end at the processing station
a step for providing a reject location for receiving rejected blanks;
a step for providing a blank pickup unit;
a step for lifting a blank from the input location with the pickup unit;
a step for sensing for the presence of more than one blank at the pickup-unit;
if a number of blanks are sensed, a step for delivering the pickup unit to the reject location and releasing the blanks; or
if only one blank is sensed, a step for delivering the blank to the upstream end of the conveyor.
In still another of its aspects, there is provided a method for increasing the processing speed of a laser blanking line, comprising the steps of:
providing two input locations for providing a source for two sets of blanks in a first group;
providing a travel path having an upstream end, the travel path extending though a shearing station to a laser welding station;
providing a reject location for receiving rejected blanks;
providing a pair of blank pickup units, one adjacent each of the input locations;
lifting a blank from the input location with each pickup unit;
sensing for the presence of more than one blank at each pickup unit;
if a number of blanks are sensed, delivering the pickup unit to the reject location and releasing the blanks;
if only one blank is sensed, delivering the blank to the travel path for delivery to the shearing station
shearing one end of each of the blanks; and
delivering the blanks to the laser welding station along the travel path for welding together the sheared ends of the blanks to form a welded blank.